Device for adjusting parts which can move in relation to each other

ABSTRACT

A device for adjusting parts which can move in relation to each other, especially parts of adjustable furniture, comprising: a driveable threaded hollow spindle ( 1 ) whose inner and outer threads increase in opposing directions; an inner spindle ( 2 ) which cooperates with the inner thread of the threaded hollow spindle ( 1 ) and which is connected to a first fixing device in order to secure the device to one of the moveable parts; and a propulsive tube ( 4 ) cooperating with the outer thread of the threaded hollow spindle ( 1 ) via an outer nut ( 3 ), whereby said tube is connected to a second fixing device ( 6 ) enabling fixation on one of the parts which can move in relation to each other. In order to keep the area between the parts which can move in relation to each other as small as possible, the threaded hollow spindle ( 1 ) is mounted in a rotationally fixed and longitudinally displaceable manner on a catch device which can be rotationally driven around the axis of the hollow spindle ( 1 ).

[0001] The invention relates to a device for adjusting parts which canmove in relation to each other, especially parts of adjustablefurniture, comprising a driveable threaded hollow spindle, whose innerand outer threads rise in opposing directions, an inner spindle whichinteracts with the inner thread of the threaded hollow spindle and whichis connected to a first fixing device in order to secure the device toone of the moveable parts, and a propulsive tube which interacts withthe outer thread of the threaded hollow spindle via an outer nut and isconnected to a second fixing device enabling fixation of the device onanother of the parts which can move in relation to each other, where thethreaded hollow spindle is mounted in a rotationally fixed andlongitudinally displaceable manner on a catch device which can berotationally driven about the axis of the threaded hollow spindle, andwhere a guard is provided for the threaded hollow spindle that extendsessentially over the length of the same.

[0002] A device of this kind enables longer travel paths between thefixing devices compared to conventional adjusting devices, whichexclusively use a spindle with an outer thread and an adjusting nut thattravels on it. While the travel path of such an adjusting devicecorresponds to the path travelled by the adjusting nut, the travel pathof a device of the kind described in the opening paragraph correspondsto the sum of the path travelled by the nut on the threaded hollowspindle and the simultaneous displacement of the inner spindle. If theopposing pitches of the inner and outer threads of the threaded hollowspindle are the same, for example, twice the travel path can be achievedcompared to a spindle equipped with only an outer thread.

[0003] A device of the kind described in the opening paragraph is knownfrom DE 196 00 326 A1. In this device, the drive and the threaded hollowspindle form a single unit, where the drive motor is mounted on one endof the threaded hollow spindle and drives it via a worm gear pair. Onsaid end, the inner spindle emerges from the threaded hollow spindle andits far end is connected to a first fixing device for connecting thedevice to one of the parts that can move relative to the other. Locatedon the opposite side of the drive motor are the outer nut, whichinteracts with the outer thread of the threaded hollow spindle, and thepropulsive tube, on whose free end the second fixing device is mountedfor connecting the device to another of the parts that can move relativeto one another.

[0004] While the inner spindle and the propulsive tube are held in placeby the fixing devices such that they cannot twist relative to the partsthat can move relative to one another, the unit comprising the worm gearpair and the threaded hollow spindle is supported in a flat rail on theinner spindle and the unit comprising the propulsive tube and the outernut. When the threaded hollow spindle is driven, this unit thereforemoves together with the drive motor relative to the two fixing devices,thereby travelling towards the first fixing device by the distance ofthe travel path relative to the inner spindle, and towards the secondfixing device by the distance of the travel path relative to the outernut and the propulsive tube. Because the drive motor protrudesconsiderably beyond the already fairly wide threaded hollow spindle, theknown device not only takes up rather a large amount of space, but alsoentails a risk of objects getting caught between the drive motor and thepart connected to the first fixing device, in particular, as well asother safety risks when it is exposed on the outside of a piece offurniture, for example. In order to avoid such risks, the knowndevice—if accessible from the outside—must be encased in a relativelylarge protective housing. If the device is used to adjust the height ofa table, for example, the table must have a relatively thick supportcolumn that obstructs the user and is unsightly.

[0005] DE 39 10 814 A1 describes a generic device for adjusting partsthat can move relative to each other, where the threads of the threadedhollow spindle and the inner spindle are protected by caps connected tothem, each of which extends essentially over the length of the threadedhollow spindle and the inner spindle.

[0006] Consequently, the object of the present invention is to furtherdevelop a device of the kind described in the opening paragraph suchthat the thread of the threaded hollow spindle is better protected.

[0007] According to the invention, the object is solved in that theguard is designed as a telescopic tube, one end of which is guided inlongitudinally sliding fashion on the propulsive tube and the other endof which is mounted in rotating and non-sliding fashion on the threadedhollow spindle. Advantageous embodiments are described in thesub-claims.

[0008] As a result of the design according to the invention, the catchdevice with the drive motor can be mounted in fixed position relative tothe second fixing device connected to the propulsive tube, where thedrive motor can be positioned immediately adjacent to the part capableof relative motion that is connected to the second fixing device.Because the inner spindle is mounted via the first fixing device in afixed position relative to another of the parts that can move relativeto one another, the threaded hollow spindle driven by the catch devicegoes through a rotational motion that causes displacement relative tothe inside spindle, on the one hand, and displacement relative to theouter nut with the propulsive tube, on the other. In this context, thepropulsive tube is mounted in a fixed position relative to the catchdevice in the longitudinal direction.

[0009] Because the drive motor with its housing can be positioned in theimmediate vicinity of one of the parts that can move relative to theother, and is spaced apart from the part connected to the inner spindleby a distance at least equal to the length of the threaded hollowspindle, there is no risk of objects getting caught or any other safetyproblems during adjustment. A relatively slim housing that closelyencases the threaded hollow spindle and the inner spindle is sufficientfor protecting the threaded hollow spindle and the inner spindle on theoutside. If the device according to the invention is used in a supportcolumn of a table to adjust the height of the table, for example, thesupport column can be of relatively slim design, thus allowing moreleg-room for a person sitting or standing at the table and achieving anaesthetically pleasing appearance.

[0010] In a preferred embodiment of the invention, the catch device isdesigned as a profile tube, where a catch profile provided on thethreaded hollow spindle engages its profile. In this configuration, thecatch device can be mounted by very simple means on the threaded hollowspindle in a rotationally fixed and longitudinally displaceable manner.

[0011] One end of the profile tube is advantageously connected to theshaft of a drive motor in non-rotating fashion. The drive motor can havea worm gear pair, for example, so that it can be arranged in arelatively slim, laterally protruding housing, e.g. underneath atabletop of adjustable height.

[0012] In a preferred embodiment of the invention, one end of theprofile tube extends into the threaded hollow spindle and has a minimuminside diameter that is greater than the outer thread diameter of theinner spindle. In this context, the catch profile is mounted on theinside of the threaded hollow spindle on the end facing the profiletube.

[0013] The end of the threaded hollow spindle facing away from theprofile tube is expediently provided with a constriction, in which theinner thread is formed. The rest of the inside area of the threadedhollow spindle is designed to accommodate the profile tube in slidingfashion. The constriction can be an integral part of the threaded hollowspindle, or firmly connected as a separate nut to a tubular hollowshaft.

[0014] In a simple configuration, the profile tube has two, oppositeperforations extending in the longitudinal direction, into which thecatch profile engages with radially inward projections. The perforationscan extend up to the vicinity of the two ends of the profile tube.

[0015] At the end facing away from the outer nut, the propulsive tubecan be connected to the housing of a motor that drives the catch device.In this configuration, the propulsive tube, the drive motor with itshousing, and the catch device, which can be designed as a profile tube,for example, can form a single unit.

[0016] The second fixing device is expediently mounted on the side ofthe housing facing away from the propulsive tube, in concentric fashionrelative to the rotational axis of the catch device.

[0017] To protect the threaded hollow spindle on the outside, an innertelescopic tube extending essentially over the length of the threadedhollow spindle can be provided, one end of which is guided inlongitudinally sliding fashion on the propulsive tube and the other endof which is mounted in rotating and non-sliding fashion on the threadedhollow spindle.

[0018] For further protection of the inner spindle on the outside, anouter telescopic tube extending essentially over the length of the innerspindle can be provided, one end of which is guided in longitudinallysliding fashion on the inner telescopic tube and the other end of whichis mounted in non-sliding and non-rotating fashion relative to the innerspindle. The first fixing device for mounting the device on one of theparts that can move relative to the other, can be designed such that theends of the inner spindle and the outer telescopic tube facing away fromthe catch device are connected in non-rotating fashion to a plate-shapedfoot perpendicular to them. A foot of this kind could, as one of theparts which can move relative to the other, form the supporting base ofa table of adjustable height, while the other part, capable of absolutemotion in the present example, would be the tabletop.

[0019] In order to limit the travel path, the inside of the propulsivetube is preferably equipped with limit switches that can be actuated bythe threaded hollow spindle.

[0020] A practical example of the present invention is explained in moredetail below on the basis of the drawing. The figures show thefollowing:

[0021]FIG. 1A device for adjusting parts that can move relative to eachother, which can particularly be used to adjust the height of a table,in the fully retracted position, and

[0022]FIG. 2 The device according to FIG. 1 in fully extended position.

[0023] As shown in the drawing, the device essentially comprises adriven threaded hollow spindle 1, with inner and outer threads inopposing directions, an inner spindle 2 that interacts with the innerthread of threaded hollow spindle 1, and a propulsive tube 4 thatinteracts via an outer nut 3 of threaded hollow spindle 1. The free endof inner spindle 2 is connected in non-rotating fashion to aplate-shaped foot 5, which can form the base of a table of adjustableheight. The connection to foot 5 forms the first fixing device of thedevice. Second fixing device 6, e.g. for connecting the adjusting deviceto the underside of a tabletop, is connected to propulsive tube 4 in amanner described in more detail below.

[0024] As shown in the drawing, threaded hollow spindle 1 is mounted ina rotationally fixed and longitudinally displaceable manner on catchdevice 7, which can be rotationally driven about the axis of threadedhollow spindle 1.

[0025] Propulsive tube 4 connected to second fixing device 6 is fixed inthe longitudinal direction relative to catch device 7. The rotation ofdriven catch device 7 causes threaded hollow spindle 1 to rotate,whereby it moves in the longitudinal direction relative to catch device7 due to its interaction with outer nut 3 of propulsive tube 4. Therelative displacement of threaded hollow spindle 1 is made possible byits longitudinally displaceable mounting on catch device 7.

[0026] As the drawing shows further, catch device 7 is designed as aprofile tube, whose profile is engaged by a catch profile 8 provided onthreaded hollow spindle 1. One end of the profile tube is connected innon-rotating fashion to motor shaft 9 of drive motor 10. Drive motor 10is mounted in housing 11, which is mounted on the end of profile tube 4that is opposite outer nut 3, where this end forms an opening for thepassage of catch device 7, which is connected in fixed fashion to motorshaft 9. Second fixing device 6 is mounted in fixed position on the sideof housing 11 facing away from propulsive tube 4, in concentric fashionrelative to the rotational axis of catch device 7. Fixing device 6 is ofplate-shaped design to allow mounting on the underside of a tabletopwith screws, for example.

[0027] Drive motor 10 has a worm gear pair, meaning that it can beaccommodated in a relatively slim housing extending laterally directlyunderneath the tabletop.

[0028] Housing 11 can be connected as a single piece, e.g. in the formof two housing shells, to the propulsive tube (which also comprises twoshells in this case), or flanged-mounted on propulsive tube 4.

[0029] The catch device, which is designed as a profile tube, has twoopposite perforations 12 extending in the longitudinal direction, intowhich catch profile 8 engages with radially inward projections. Theperforations extend up to the vicinity of the two ends of the profiletube.

[0030] The end of threaded hollow spindle 1 facing away from catchdevice 7 is provided with an inside nut 13, which interacts with innerspindle 2. Inside nut 13 can be designed as an integral constriction ofthreaded hollow spindle 1, or connected to threaded hollow spindle 1 asa separate part.

[0031] The remaining area of threaded hollow spindle 1 is designed toaccommodate catch device 7, which is designed in the form of a profiletube, in sliding fashion. Catch profile 8 comprises two opposite notchesat corresponding points on threaded hollow spindle 1.

[0032] Catch device 7, which is designed in the form of a profile tube,inside nut 13, the remaining area of threaded hollow spindle 1 and innerspindle 2 are radially dimensioned such that the outer thread diameterof inner spindle 2 is smaller than the inside diameter of the profiletube.

[0033] To protect threaded hollow spindle 1 and inner spindle 2 on theoutside, inner and outer telescopic tubes 14 and 15 are provided, whichcannot rotate relative to propulsive tube 4. One end of inner telescopictube 14 is guided in longitudinally sliding fashion on propulsive tube 4and the other end is mounted in rotating and non-sliding fashion on thethreaded hollow spindle by means of ball bearing 16, while one end ofouter telescopic tube 15 is guided in longitudinally sliding fashion oninner telescopic tube 14, and the other end is mounted in non-slidingand non-rotating fashion relative to inner spindle 2. In the embodimentshown in the drawing, outer telescopic tube 15 is mounted in fixedposition on foot 5 for this purpose.

[0034] To limit the travel path, the inside of propulsive tube 4 isequipped with limit switches 17 that can be actuated by the threadedhollow spindle.

LIST OF REFERENCE NUMBERS

[0035]1. Threaded hollow spindle

[0036]2. Inner spindle

[0037]3. Outer nut

[0038]4. Propulsive tube

[0039]5. Foot

[0040]6. Second fixing device

[0041]7. Catch device

[0042]8. Catch profile

[0043]9. Motor shaft

[0044]10. Drive motor

[0045]11. Housing

[0046]12. Perforation

[0047]13. Inside nut

[0048]14. Inner telescopic tube

[0049]15. Outer telescopic tube

[0050]16. Ball bearing

[0051]17. Limit switch

1. Device for adjusting parts which can move in relation to each other,especially parts of adjustable furniture, comprising a driveablethreaded hollow spindle (1), whose inner and outer threads rise inopposing directions, an inner spindle (2) which interacts with the innerthread of the threaded hollow spindle (1) and which is connected to afirst fixing device in order to secure the device to one of the moveableparts, and a propulsive tube (4) which interacts with the outer threadof the threaded hollow spindle (1) via an outer nut (3) and is connectedto a second fixing device (6) enabling fixation of the device on anotherof the parts which can move in relation to each other, where thethreaded hollow spindle (1) is mounted in a rotationally fixed andlongitudinally displaceable manner on a catch device (7) which can berotationally driven about the axis of the threaded hollow spindle (1),and where a guard is provided for the thread of the threaded hollowspindle (1) that extends essentially over the length of the same,characterised in that the guard is designed as a telescopic tube (14),one end of which is guided in longitudinally sliding fashion on thepropulsive tube (4) and the other end of which is mounted in rotatingand non-sliding fashion on the threaded hollow spindle (1).
 2. Deviceaccording to claim 1, characterised in that the catch device (7) isdesigned as a profile tube, whose profile is engaged by a catch profile(8) provided on the threaded hollow spindle (1).
 3. Device according toclaim 2, characterised in that one end of the profile tube is connectedto the motor shaft (9) of a drive motor (10) in non-rotating fashion. 4.Device according to claim 2 or 3, characterised in that one end of theprofile tube extends into the threaded hollow spindle (1) and has aminimum inside diameter that is greater than the outer thread diameterof the inner spindle (2), and the catch profile (8) is mounted on theinside of the threaded hollow spindle (1) on the end facing the profiletube.
 5. Device according to claim 4, characterised in that the end ofthe threaded hollow spindle (1) facing away from the profile tube isprovided with a constriction, in which the inner thread is formed, andthe remaining area is designed to accommodate the profile tube insliding fashion.
 6. Device according to claim 5, characterised in thatthe profile tube has two, opposite perforations (12) extending in thelongitudinal direction, into which the catch profile (8) engages withradially inward projections.
 7. Device according to one of claims 1 to6, characterised in that the propulsive tube (4) is connected at the endfacing away from the outer nut (3) to the housing (11) of a motor (10)that drives the catch device (7).
 8. Device according to claim 7,characterised in that the second fixing device (6) is mounted on theside of the housing (11) facing away from the propulsive tube (4). 9.Device according to one of claims 1 to 8, characterised in that an outertelescopic tube (15), relative to the first telescopic tube (14),extending essentially over the length of the inner spindle (2) isprovided, one end of which is guided in longitudinally sliding fashionon the inner telescopic tube (14) and the other end of which is mountedin non-sliding and non-rotating fashion relative to the inner spindle(2).
 10. Device according to claim 9, characterised in that the ends ofthe inner spindle (2) and the outer telescopic tube (15) facing awayfrom the catch device (7) are connected in non-rotating fashion to aplate-shaped foot (5) perpendicular to them.
 11. Device according to oneof claims 1 to 10, characterised in that the inside of the propulsivetube (4) is equipped with limit switches (17) that can be actuated bythe threaded hollow spindle (1).